This means that any change in vertical speed is due to gravitational acceleration, which is 9.81 m/s2 (32.2 ft/s2) on Earth. y = h + t * V_y - g * t_2 / 2. The order of the points does not matter for the formula as long as the points chosen are consistent. Keep reading to learn more about this calculator along with other helpful information you need when learning about projectile motion. A meter is approximately 3.28 feet. It calculates the unknown angle by using the given angles of the two lines.